Liquid fuel control mechanism



Aug. 25, 1959 A. CHADWICK 2,901,030

LIQUID FUEL CONTROL MECHANISM Filed Feb. 8, 1955 2 Sheets-Sheet 1 vINVEN 10 R.

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United States Patent @fiice 2,901,030 Patented Aug. 25, 1959 LIQUID FUELCONTROL MECHANISM Alexander Chadwick, Inkster, Mich., assignor toChrysler Corporation, Highland Park, Mich., a corporation of DelawareApplication February 8, 1955, Serial No. 486,816

2 Claims. (Cl. 158-364) My instant invention relates generally to liquidfuel combustion apparatus and to fuel control mechanisms for usetherewith. More particularly, my instant invention comprises a new andimproved control valve assembly which is particularly adapted to be usedwith and form a part of a fuel system for a gas turbine power plant,although it is contemplated that it is also capable of being used withother types of fuel combustion apparatus.

My instant invention represents an improvement in the fuel controlmechanism described in my copending US patent application Serial Nos.452,568 and 452,569, filed August 27, 1954, which is assigned to theassignee of my instant invention, the latter application being nowabandoned.

For the purpose of illustrating the novel features of my invention, Ihave presently disclosed the same in combination with a gas turbinepower plant of the automotive type but it will become apparent that myinvention is not restricted in use to power plants of this type.

In general, a gas turbine power plant of the type herein disclosed maycomprise a liquid fuel burner mechanism, air intake passage means forsupplying the burner with combustion supporting air, an air compressorfor compressing the intake air before it enters the burner mechanism,and at least two rotary turbine stages which are adapted to be poweredby the combustion gases produced within the burner mechanism, one stagebeing drivably coupled to the compressor for powering the same and theother being drivably connected to a speed reduction transmission whichin turn is adapted to deliver power to a power absorbing means such asthe driving wheels of a Wheeled vehicle. A rotatable exhaust gas passagemeans is provided for transferring the exhaust gases from the downstreamside of the rotary turbine stages to the exterior of the power plant. Aregenerator' mechanism is preferably provided for utilizing a largeportion of the thermal energy of the hot exhaust gases to raise thetemperature of the compressed intake air before it is caused to enterthe burner mechanism as above described.

The fuel system of which my instant invention forms a part includes afuel and air pumping unit which may be powered by the above describedfirst turbine stage. This pumping unit has been previously disclosed inthe copending application of David W. Barton, Serial No. 440,932, filedJuly 2, 1954, which is assigned to the as.- isignee of my instantinvention, and it includes a fuel pumping chamber and an air pumpingchamber, each of said chambers being partly defined by a spring loadedpumping diaphragm.

An air atomizing nozzle is provided within the above mentioned burnermechanism for producing a combustible spray of liquid fuel and separatedelivery conduit means are disposed between the air atomizing nozzle andeach of the pumping chambers. Another conduit is provided for deliveringhigh pressure air from the discharge side of the turbine compressor tothe intake side of the air pumping chamber of the pumping unit. Thedis,- charge side of the air pumpingchamber is interconnected with thefuel pumping portion of the pumping unit so that the air pressure at thedischarge side of the air pumping chamber is adapted to act upon thefuel diaphragm for the fuel pumping chamber to supplement the pumpingaction of a fuel pumping spring which is provided for this purpose.

The improved fuel control mechanism of my instant invention may bedisposed in the fuel delivery conduit interconnecting the fuel pumpingportion of the above described pumping unit and the air atomizing nozzleand it is sensitive to operating variables of the gas turbine engine forcontrolling and scheduling the flow of liquid fuel to the air atomizingnozzle so that the fuel-air ratio within the burner mechanism will bemaintained at a predetermined optimum value during operation of theengine at varying speeds and loads and during variations in. the engineoperating conditions.

The control valve mechanism of my instant invention is somewhat similarin function to the control valve mechanism described in my abovementioned copending applications, Serial Nos. 452,568 and 452,569, butit is unique in that it is characterized by its greater simplicity. Theprovision of a fuel control mechanism with this characteristic being aprincipal object of my instant invention, it is another object of myinvention to provide a fuel control mechanism which is possessed of ahigh degree of reliability.

Another object of my invention is to provide a fuel control mechanism ofthe type referred to above in which the component elements thereof arerelatively few in number and are arranged in a composite assembly withminimum space requirements.

It is another object of my instant invention to provide a fuel controlmechanism for use with a power plant of the type mentioned above whichincludes a first valve means for regulating the flow of liquid fuel tothe power plant burner mechanism during starting and during accelerationof the turbine elements up to :a normal idling speed.

It is a further object of my invention to adapt the first valve means,mentioned in the preceding object, to function as an idle speed governorvalve to limit the speed of the engine turbine elements to apredetermined maximum idling speed.

It is a further object of my instant inventionto provide a fuel controlmechanism of the type set forth in the preceding object wherein a secondvalve means is operatively associated with the first valve means and iseffective to control and to schedule the flow of fuel to the power plantburner mechanism during acceleration of the turbine elements from anidling speed to a predetermined maximum speed.

It is a further object of my instant invention to adapt the abovementioned second valve means to function as a turbine speed governorvalve for limiting the turbine speeds to values below a predeterminedlimiting value.

It is a further object of my instant invention to provide a fuel controlmechanism of the type set forth in the preceding object wherein apersonally operable throttle valve. is provided for use in combinationwith the above mentioned first and second valve means and which iseffective to permit regulation of the flow of fuel to the power plantburner mechanism, said second valve means being disposed in series withthe throttle valve in a common fuel flow path.

It is a further object of my instant invention to provide a fuel controlmechanism of the type above set forth wherein the valve componentsthereof are disposed in the fuel flow path extending from a fueldelivery ptnnping mechanism and the power plant burner mechanism andwherein regulator valve means are provided for maintaining. the pressuredifferential across the valve compo- 3 nents at a substantially constantvalue, said regulator valve means being of an improved and simpleconstruction. p

It is a further object of my instant invention to provide a fuel controlmechanism of the type above set forth wherein additional valve means areincluded for correcting the rate of fuel flow to the power plant burnerfor variations in ambient air pressure, said additional valve meansbeing effective to maintain the fuel-air ratio within the power plantburner at a constant value during variations in ambient air pressure.

It is a further object of my instant invention to provide a new andimproved liquid fuel control mecharusm which includes a personallyoperable throttle valve a plurality of fuel flow regulating valves andan ambient air pressure compensating valve, each of said valvesincluding a flow restricting orifice and a movable valve elementregistering with the orifices to vary the rate of fuel flowtherethrough, said orifices forming a portion of the fuel fiow pathextending to the power plant burner.

It is a further object of my invention to form the above mentioned firstand second valve means with a common, movable valve element forcontrolling the flow of fuel through the respective orifices, saidcommon valve element including separate valving portions for cooperatingwith each of said orifices.

It is a further object of my instant invention to provide a fuel controlmechanism as above set forth wherein the valve elements thereof arecharacterized by their simplicity and by their relatively lowmanufacturing cost.

It is a further object of my instant invention to provide a fuel controlmechanism capable of controlling the distribution of liquid fuel to theburner of a fuel combustion apparatus so that the fuel requirements ofthe latter are automatically accommodated throughout the entireoperating speed and load range.

For the purpose of particularly pointing out the new and unique featuresof my invention, reference will be made herein to the accompanyingdrawings:

Figure l is a schematic representation of an automotive type power plantcapable of employing a fuel control mechanism of my instant invention;

Figure 2 is a sub-combination view taken along section line 22 of Figure1 showing the schematic arrangement of the fuel and air pumping unit andthe means for powering the same;

Figure 3 is a cross sectional view of the power plant fuel and airpumping mechanism which is shown schematically in Figures 1 and 2;

Figure 4 is a cross sectional view of the pumping unit of Figure 3 takenalong section line 44 of Figure 3; and

Figure 5 is a schematic representation of the fuel control mechanism ofmy instant invention and it shows the principal valve components.

Referring first to the schematic power plant assembly view of Figure 1,a rotary turbine compressor is designated by numeral 10 and it includesa bladed rotor 12 and an intake air opening 14. Air is conducted throughthe intake opening 14 andis discharged radially from the periphery ofthe bladed rotor 12 at an increased pressure. The pressurized intake airis caused to pass through a first regenerator passage means 16 into thevicinity of a power plant burner which is generally designated in Figure1 by numeral 18. The compressed intake air is caused to enter theinterior of a burner cone 20 where it is mixed with a spray of atomizedliquid fuel which is discharged by a fuel atomizing nozzle 22. Theliquid fuel is burned within the burner 20 and the combustion gases arecaused to pass through a twostage turbine assembly generally designatedby means of numeral 24. This turbine assembly comprises a first turbinestage 26 and a second turbine stage 28 which are rotatably mounted incoaxial adjacent relationship.

After passing through the two-stage turbine assembly 24, the motivegases are conducted through a suitable passage means 30 into a secondregenerator passage means 32. The exhaust gases are then exhaustedthrough a suitable exhaust portion as shown at 34. The relatively hotexhaust gases passing through the regenerator passage means 32 areeffective to increase the temperature of the relatively coolercompressed intake air passing in the opposite direction through theregenerator passage means 16. This transfer in thermal energysubstantially increases the thermal efficiency of the power plant.

An igniter plug 36 is provided, as shown, within the burner tube 20 forthe purpose of initiating combustion during the starting cycle of thepower plant. After the turbine elements have attained a normal idlingspeed, the igniter plug 36 may be deenergized and thereafter combustionwithin the burner tube 20 will be self-sustaining.

The second turbine stage 28 functions as a power turbine and it may bedrivably coupled to a suitable speed reduction transmission 38 which inturn may be connected to a power absorbing means such as the vehicledriving wheels. The first turbine stage 26 functions as a compressorturbine and it is drivably coupled to the turbine rotor 12 by means ofshafting 40.

A liquid fuel and air pumping unit is generally designated in Figures 1and 2 by means of numeral 42 and it includes a rocker arm 44 foractuating the pumping elements thereof. The arm 44 is adapted to contacta cam 46 which is integrally connected to a shaft 48. This shaft 48 maybe powered by the compressor rotor shafting 40 and it is drivablyconnected thereto by suitable gearing 50, said gearing 50 including afirst gear 52 drivably connected to the shafting 40 and an intermeshinggear 54 drivably connected to the shaft 48.

The fuel and air pumping unit 42 is supplied with liquid fuel by areservoir 56 as schematically shown in Figure 1, said reservoir beingconnected to the inlet side of the fuel and air pumping unit 42 by meansof a fuel supply conduit 58. The pumping unit 42 is supplied withpressurized intake air from the compressor 10 by means of an air supplyconduit 60. A high pressure fuel delivery conduit 62 interconnects thedischarge side of the fuel pumping portion of the pumping unit 42 withthe liquid fuel atomizing nozzle 22 and the fuel control mechanism of myinstant invention is interposed in the delivery conduit 62, as shown at64 in Figure 1. High pressure or delivery conduit 66 is interconnectedbetween the air pumping portion of the pumping unit 42 and the fuelatomizing nozzle 22. The air delivered through the conduit 66 to thenozzle 22 is utilized to atomize the liquid fuel into a combustiblespray within the burner cone 20.

Referring next to Figures 3 and 4, the above-described fuel and airpumping unit 42 is shown in more particular detail and it includes afirst body portion 68 which is formed with a central opening 7t) withinwhich the above-mentioned rocker arm 44 is pivoted, the fulcrum pin forthe arm 44 being shown at 72. The arm 44 includes an extension 74 whichextends inwardly within the opening 70 and it is adapted to looselyengage an air diaphragm actuating shaft 76 which is disposed in avertical direction as shown in Figures 3 and 4. The shaft 76 is slidablysituated within an aperture 78 formed in another housing portion 80which may be positioned upon the upper surface of the intermediate pumphousing portion 68. An upper pump housing portion 82 is situated abovethe housing portion 80 and a flexible air diaphragm 84 is situatedbetween the juxtaposed surfaces of the housing portions 80 and 82. Theair diaphragm 84 is effective to define with the housing portion 80 anair pumping chamber 86 and is also effective to define with the housingportion 82 a spring chamber 88. The diaphragm actuator shaft 76 isconnccted at its upper end to the center of the air diaphragm 80 bysuitable fastening means 90. An air pumping spring 92 is disposed withinthe spring chamber 88 for the purpose of biasing the diaphragm 84 andthe diaphragm actuating shaft 76 in a downward direction.

As best seen in Figure 4, the air supply conduit 60 communicates with aninner chamber 94 which communicates with the abovedescribed air pumpingchamber 86 through a one-way check valve mechanism 96, said check valvemechanism including an orifice plate 98 and a spring loaded valveelement 100 for selectively blocking the orifice formed in the orificeplate 98. The spring chamber 88 communicates with the inner chamber 94through a suitable air. passage 102 to accommodate the displacement ofair during movement of the air diaphragm 84.

The air pumping chamber 86 also communicates with another inner chamber104 through a second one-way check valve mechanism 106, said mechanism106 including an orifice plate 108 and a movable spring loaded valveelement 111% The chamber 104 communicates with the air delivery conduit66 for the nozzle 22 as shown.

Another pump housing portion 112 is mounted against the lower surface ofthe intermediate housing portion 68 and a flexible fuel diaphragm114 issecured between the juxtaposed surfaces of the housing portions 68 and112. The fuel diaphragm 114 is adapted to define with the housingportion 112 a fuel pumping chamber 116 and is adapted to define with theintermediate housing portion 68 a fuel spring chamber 118, said springchamber 118 containing a fuel spring 119 which is adapted to urge thefuel diaphragm 114 in a downward direction. The center of the fueldiaphragm 113 is secured to a diaphragm actuating shaft 120 by suitablefastening means 122. The shaft 128 llS slidably received within avertical opening 124 and it is joined to the rocker arm extension 74 bymeans of a lost motion connection. This lost motion connection consistsof a washer element 126 secured to the end of shaft 120 and an opening128 through which the shaft 128 is loosely received.

The fuel pumping chamber 116 is in communication with an interior cavity130- through a one-Way check valve 132 which is similar in constructionto the abovementioned check valves 96 and 106. Cavity 130 is in fluidcommunication with the fuel supply conduit 58 as shown.

The fuel pumping chamber 116 is also in communication with anothercavity 134 through another check valve 136 and this cavity is in fluidcommunication with the fuel delivery conduit 62. The check valve 132 isadapted to admit fuel into the chamber 116 during an upward movement ofthe fuel diaphragm 114 and the check valve 136 is effective to allow thefuel to pass from the chamber 1116 into the cavity 134 and the deliveryconduit 62.

The pump housing also includes a lower housing portion 138 whichdefines: a surge chamber 140. A flexible diaphragm 142 is extendedacross the surge chamber 140 and is spring biased in an upper directionby spring 144. The upper surface of the diaphragm 142 is exposed to fueldischarge pressure within the cavity 134. An air passage 1.46 isprovided, as shown, between the air delivery conduit and the surgechamber 140 for the purpose of charging the latter with high pressureair. The spring chamber 118 for the fuel pumping portion of the unit isin fluid communication with chamber 104 through a passage 148.

During the operation of the power plant, the gearing 58 is effective torotate the cam 46 which in turn causes the rocker arm to oscillate aboutits pivot point 72. During a clockwise movement of the rocker arm 44, asviewed in Figure 3, the air diaphragm 84 and the fuel diaphragm 114 aremoved vertically upward against the opposing forces of the springs 92and 119 respectively. During this upward stroke, the valve 96 iseffective to admit air into the air pumping chamber 86 and the valve 132is effective to admit fuel into the fuel pumping chani-' her 116. Whenthe rocker arm 44 moves in a counterclockwise direction, the rocker armextension 74 becomes disengaged from each of the actuator shafts 76 and120. A spring is provided, as shown in Figure 3, for the purpose ofnormally biasing the rocker arm 44 in a counterclockwise direction. Thefuel diaphragm 114 moves downwardly under the influence of fuel spring119 while the air diaphragm 84 moves downwardly under the influence ofthe air spring 92. During this downward movement air is delivered to theair delivery conduit 66 through the check valve 106. Also high pressurefuel is delivered to the fuel delivery conduit 62 through the checkvalve 136. The surge chamber 140 is adapted to maintain a substantiallyuniform pressure in the fuel delively conduit 62 by virtue of thepressure exerted by the spring 144 and the air contained within thechamber 140.

Refer-ring next to Figure 5, the fuel control mechanism 64 of my instantinvention is shown in detail and it comprises a multiple piece housingwhich may consist of six housing portions shown at 152 154, 156, 158,160, and 162. These various housing portions may be assembled in stackedrelationship and held together as an integral unit by clamping bolts164. A suitable gasket may be disposed between the juxtaposed surfacesof each of the above-mentioned housing portions. The housing portions152 and 154 are adapted to define a pair of chambers 166 and 168respectively, which are separated by a flexible diaphragm 170, saiddiaphragm 170 being secured about its periphery between the juxtaposedsurfaces of the housing portions 152 and 154. The charn' her 166 is influid communication with the fuel delivery conduit 62 through a valveport 172. A valve element 174 is carried by the flexible diaphragm 170and it is effective to automatically maintain a substantially constantpressure differential between the chambers 166 and 168. A spring 176 isprovided to normally urge the valve 174 toward an open position. Thechamber 168 is in communication with the fuel supply conduit 62 asshown.

The pump housing portions 158 and 156 are adapted to define a chamber178 which is separated from the chamber 168 by a wall 180 which forms aportion of the pump housing portion 154. A fuel metering orifice 182 isformed in the wall 180 and a metering rod 184 is situated within theorifice 182 for the purpose of varying the rate of fuel flow from thechamber 168 to the chamber 178. The metering rod 184 extends outwardlythrough an opening 186 formed in the housing portion 158 and it issecured at its outer end to a pressure bellows 188. The bellows 188forms a portion of an altitude capsule 190 which may include acylindrical cup 192 having means 194 for securing the same to thehousing portion 158. The cup 192 may be closed by a disc 196 to whichone end of the bellows 188 is secured. A spring 198 may be interposedbetween the disc 196 and the metering rod 184.

A tapered section 280 is formed on the metering rod 184 and it isadapted to cooperate with the orifice 182 to provide a controlledrestriction for the flow of fuel. When the ambient air density decreasesby reason of a decrease in ambient air pressure or an increase inambient air temperature, the capsule 188 expands thereby moving themetering rod 188 to the left as viewed in Figure 5, and this in turnincreases the degree of restriction provided by the orifice 182. Thisdecreased rate of fuel flow compensates for the decrease in mass rate offlow of air to the nozzle 22 which accompanies such a decrease inambient air pressure and the fuel air ratio is thereby maintained to asubstantially constant value.

The housing portions 154 and 156 are effective to define a pair ofchambers 202 and 204, the former communicating with chamber 178 througha passage 206. Passage 208 provides communication between the chambers202 and 204.

The housing portions 156, 158, and 160 are adapted to define anotherchamber 210 which is in fluid communication with the above-mentionedchamber 202 through a metering orifice 212. Another metering rod isshown at 214 and it includes a tapered section 216 which cooperates withthe metering orifice 212 to vary the rate of fuel flow from the chamber202 into the chamber 210. The metering rod 214 extends outwardly throughan opening 218 formed in the housing portion 160. A suitable dashpotmechanism is schematically shown at 220 and it is adapted to dampen themovement of the metering rod 214. An accelerator pedal lever is shown at222 and it is pivoted at 224 to the housing portion 162. Upon movementof the lever 222 in a counterclockwise direction about its pivot point224, it is effective to move the metering rod 214 to the left and tothereby progressively open the metering orifice 212 to provide anincreased flow of fuel from the chamber 262 to the chamber 210. When theaccelerator pedal lever 222 moves in the opposite direction, themetering rod 214 moves to the right as viewed in Figure to restrict theorifice 212. The dashpot mechanism 220 is effective to retard the rateof movement of the metering rod 214 thereby preventing a sudden decreasein the rate of fuel delivery which could cause a flame blowout in thepower plant burner.

The housing portions 158 and 160 are also adapted to define a chamber226 and the housing portions 156 and 158 are also adapted to define achamber 228. The chamber 226 and 228 are separated by a wall 239 whichforms part of the housing portion 158. The chambers 228 and 284 areseparated by a wall 232 forming a portion of housing portion 156.Metering orifices are formed at 234 and 236 in the Walls 236 and 232respectively. A metering rod 238 is positioned within each of theorifices 234 and 236 and it includes two tapered sections 248 and 242which respectively cooperate with the orifices 234 and 236.

Housing portions 160 and 162 are adapted to define a pair of chambers244 and 246 which are separated by a flexible diaphragm 248 as shown.The metering rod 238 extends through an opening 250 formed in thehousing portion 160 and is secured to the flexible diaphragm 248. Aspring 252 may be provided to normally bias the diaphragm 248 and themetering rod 238 toward the right as viewed in Figure 5. The chamber 246is in fluid communication with the high pressure side of an engineddriven speed sensor unit shown schematically at 254, said speed sensorunit including a conventional rotor element 256 which is effective toestablish a centrifugal head at its periphery. Upon an increase inengine speed, the pressure within the chamber 246 is increased therebybiasing the metering rod 238 to the left to vary the degree ofrestriction provided by the orifices 234 and 236.

During the starting cycle and during acceleration of the engine up to apredetermined idling speed, the orifice 236 and the tapered metering rodsection 240 are adapted to schedule a predetermined flow of fuel fromthe chamber 204 to the chamber 228. As the engine speed increases, theamount of fuel which is metered by the orifice 236 is increased. Thepressure drop across the orifice 236 is near a minimum value when theidling speed is reached. If the engine tends to increase in speed beyondthe normal idling speed, the metering rod 238 will be moved further tothe left which will in turn increase the degree of restriction offeredby the orifice 236. After the idling speed has been reached, the orifice236 and the metering rod section 240 function as a governor valve tolimit the turbine speed toits predetermined value.

To accelerate the engine from an idling speed to a higher operatingspeed, the metering rod 214 may be urged to the left by means of theaccelerator pedal linkage. As the metering rod 214 is moved to the left,the degree of restriction ofiered by the metering orifice 212 to theflow of fuel from the chamber 202 to the chamber 210 is progressivelydecreased. Since the metering orifice 234 is in series with the meteringorifice 212, movement of the metering rod 214 will not be accompanied byan immediate increase in fuel flow. However, as the engine speedincreases, the metering rod 238 is also moved to the left which causesthe orifice 234 to become progressively open. It is thus seen that theorifice 234 and the metering rod section 242 function as an acceleratingfuel schedule valve which is effective to limit the flow of fuel to thepower plant burner to that optimum valve which is required under anygiven set of power plant operating conditions.

Chamber 228 is in fluid communication with chamber 166 through aninternal passage 258, said chamber 166 communicating with the fueldelivery conduit 62 as previously mentioned.

A check valve 260 may be provided, as shown, in the fuel deliveryconduit 62 to prevent a reversal in the flow of fuel in the vicinity ofthe nozzle 22 into the fuel control mechanism after the engine has beenturned off.

A bypass passage between the fuel delivery conduit 62 and the fuel tank56 is provided at 262 and a bypass valve 264 is interposed in thepassage 262. The valve 264 may be actuated by means of a solenoid whichmay be energized by the ignition current when the engine is turned on toblock the passage 262. When the ignition current is turned off, thesolenoid actuating mechanism may retract the bypass valve element toopen the bypass passage 262.

It may be seen from Figures 3 and 4 that the differential between thefuel delivery pressure and the air inlet pressure will tend to remainsubstantially constant throughout the operating speed range since thefuel delivery pressure is partly determined by the magnitude of the airpressure. However, it has been found that a slight variation does existas the fuel delivery rate increases from its minimum value to itsmaximum value. The pressure regulating valve 174 is effective tocompensate for this variation in pressure differential and to maintain aconstant pressure drop across the various metering valves within thevalve assembly 64. It therefore follows that the rate of fuel deliverywill be determined solely by the positions which are assumed by themetering rods 238, 214 and 184.

As previously indicated, an important feature of my instant inventionresides in the simplicity and reliability which is induced in itsconstruction. By preference, the metering rods 184, 214 and 238 areformed with a circular cross sectional shape because of the accompanyingadvantages in machining and assembly. The valving portions of themetering rods may be formed as flats with varying transverse dimensionsas shown to accommodate the passage of fuel through its associatedorifice.

I do not intend to limit my invention to the specific embodiment hereindisclosed since many variations thereof may be made without departingfrom the scope of my invention as defined by the following claims.

I claim:

1. In a liquid fuel control means for an internal combustion engine, thecombination of a fuel delivery conduit for connecting said engine with asource of pressurized fuel, throttle valve means, said conduit includinga chamber downstream of said throttle valve means, a branch conduit incommunication with the firstnamed conduit upstream of said throttlevalve means and bypassing the latter, an acceleration metering orificeand an idle metering orifice comprising portions of said first-named andbranch conduit respectively and extending through the walls of saidchamber at spaced locations, a fuel scheduling and overspeed governorvalve means, a starting fuel scheduling and idle speed governor valvemeans, the two scheduling and governor valve means comprising separatemetering rod portions on a common movable element, said separate rodportions being movable respectively within said acceleration meteringand idle metering orifices, speed responsive means operatively connectedwith said element for progressively moving the same in one direction orthe opposite with increasing or decreasing engine speed respectively,each metering rod portion having an intermediate section of reducedcross sectional area, the metering rod portion in said accelerationmetering orifice being arranged to reduce the restriction to fuel flowthrough the latter orifice progressively upon movement in said onedirection under engine accelerating conditions from a positioncorrespondingv to a predetermined idling speed to a positioncorresponding to a predetermined upper speed proximate the maximumallowable speed of said engine and to increase the restriction to fuelfiow through the latter orifice upon continued movement in said onedirection beyond said last-named position, the metering rod portion insaid idle metering orifice being arranged to reduce the restriction tofuel flow through the latter orifice progressively upon movement in saidone direction from a position corresponding to an engine startingcondition to a position corresponding to said predetermined idling speedand to restrict the fuel flow through said idle metering orificeprogressively upon continued movement of the latter metering rod portionin said one direction beyond the latter position, thereby to close saididle metering orifice at speeds above said predetermined idling speed.

2. In a liquid fuel control means for an internal combustion engine, thecombination of a fuel delivery' conduit for connecting said engine witha source of pressurized fuel, throttle valve means, said conduitincluding a chamber downstream of said throttle valve means, a branchconduit in communication with the firstnamed conduit upstream of saidthrottle valve means and bypassing the latter, an acceleration meteringorifice and an idle metering orifice comprising portions of saidfirst-named and branch conduit respectively and extending through thewalls of said chamber at spaced locations, a. fuel scheduling andoverspeed governor valve means, a starting fuel scheduling and idlespeed governor valve means, the two scheduling and governor valve meanscomprising separate metering rod portions on a common movable element,said separate rod portions being movable respectively Within saidacceleration metering and idle metering orifices, speed responsive meansoperatively connected with said element for progressively moving thesame in one direction or the opposite with increasing or decreasingengine speed respectively, each metering rod portion having anintermediate section of reduced cross sectional area, the metering rodportion in said acceleration metering orifice being arranged to reducethe restriction to fuel flow through the latter orifice progressivelyupon movement in said one direction under engine accelerating conditionswithin a range from a predetermined idling speed to adjacent the maximumallowable engine speed and to increase the restriction to fuel flowthrough the latter orifice upon movement in either direction beyond saidrange, the latter orifice being only partially closed at saidpredetermined idling speed, the metering rod portion in said idlemetering orifice being arranged to reduce the restriction to fuel flowthrough the latter orifice progressively upon movement in said onedirection from a position corresponding to an engine starting conditionto a position corresponding to said predetermined idling speed and torestrict the fuel flow through said idle metering orifice progressivelyupon con tinued movement of the latter metering rod portion in said onedirection beyond the latter position, thereby to close said idlemetering orifice at speeds above said predetermined idling speed.

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